Portable global positioning system (GPS) devices, such as the Scout by Trimble Navigation, Ltd. of Sunnyvale, Calif. and hand-held cellular telephone devices, such as the Micro Tac flip-phones by Motorola, Inc. of Schaumberg, Illinois are well known in the prior art. Combined position locating and cellular telephone devices are also known in the art. The combined position locating system and cellular telephone devices commonly operate in different regimes and function independently of each other. An example of a prior art combined position locating and cellular telephone device is shown, for example, in U.S. Pat. No. 5,043,736 to Darnell et al. The position locating portion of Darnell's device includes an antenna, an RF "L" band receiver, a position locating demodulator, a dedicated microprocessor, and RAM. The cellular telephone portion of the L band signals received at the antenna are for a global positioning system, and a cellular phone system. Prior art combined position locating and cellular telephone devices typically include a complete position locating system including a dedicated position locating microprocessor. The complete position locating system and dedicated position locating microprocessor occupy at least one printed circuit board. Prior art combined position locating and cellular telephone device further includes a complete cellular telephone system and a dedicated cellphone microprocessor for controlling cellular telephone functions. The cellular telephone system and dedicated cellphone microprocessor also occupy at least one other printed circuit board. Therefore, prior art combined position locating and cellular telephone devices have at least two microprocessor units and occupy at least two printed circuit boards or other similar substrates. Thus, prior art combined position locating and cellular telephone devices are much bulkier and are more complex than conventional stand-alone position locating or standalone cellular telephone systems.
As an additional disadvantage, prior art combined position locating and cellular telephone devices suffer from significant drawbacks. That is, prior art combined position locating and cellular telephone devices are more expensive, and are more complex than conventional stand-alone position locating or cellular telephone systems. The additional bulk, cost, and complexity associated with such devices may not appeal to a consumer.
Thus, the need has arisen for a position locating and cellular telephone combination which does not have the additional bulk, cost, and complexity associated with prior art combined position locating and cellular telephone devices.